1. Field of the Invention
The present invention relates generally to electrophotographic imaging device and particularly to a fuser assembly having a plurality of lubricant retention features defined on a heater body of the fuser assembly and dimensioned to retain the lubricant on the interior surface of a fuser belt adjacent a fuser nip.
2. Description of the Related Art
An electrophotographic imaging device, such as a laser printer, forms a latent electrostatic image on a surface of a photoconductor by selectively exposing an area of the surface to light. The latent electrostatic image is developed into a visible image by electrostatic toners that contain pigment components and thermoplastic components. A print media (e.g., a sheet of paper or a transparent sheet) is given an electrostatic charge opposite to that of the toner and then passed close to a surface of the photoconductor, pulling the toner from the photoconductor onto the sheet of paper or transparent sheet in the pattern of the image developed from the photoconductor. After the image is transferred to the print media, the print media is processed through a fuser assembly where it is heated and pressed. The fuser assembly melts and fixes the toner to the print medium surface, thereby producing a substantially permanent printed image. The fuser belt is rotated by a backup roller that is pressed against the fuser belt to form a nip. A ceramic heater is positioned in the interior surface of the fuser belt. As the fuser belt is rotated, an interior surface of the fuser belt slides on the heater surface. The sliding contact between the fuser belt and the heater surface can cause a high frictional force that is undesirable.
To reduce this frictional force, grease and oil have been commonly used as lubricants between the belt and the heater. Greases normally have higher viscosity than oil and can form thicker films on the fuser belt and heater surface. Higher viscosity can cause higher frictional force and driving torque, and thicker film thickness can increase thermal resistance and lower toner fusing capability. As the grease/oil leaves the fuser nip, the lubricant condition between the fuser belt and the heater worsens, leading to higher driving torque, higher fuser belt wear, and sometimes damaging the fuser belt.
Therefore, it would be desirable to maintain grease/oil in the fuser nip and keep the lubrication condition between the fuser belt and the heater at acceptable levels.